Lubricating system for sewing machine



Oct. 18, 1966 K. 1 JARRETT LUBRICATING SYSTEM FOR SEWING MACHINE Filed Aug. 14, 1964 y /4EV//Ig @unnunnnnnnnnmmmmnnmnnmmm INVENTOR.

KENNETH LJARRETT United States Patent O 3,279,403 LUBRICATING SYSTEM FOR SEWING MACHINE Kenneth L. Jarrett, Mertztown, Pa., assignor to The Merrow Machine Company, Hartford, Conn., a corporation of Connecticut Filed Aug. 14, 1964, Ser. No. 389,555 4 Claims. (Cl. 112256) This invention relates to lubrication systems and more particularly to an improved lubrication system for a high speed sewing machine.

This invention is specifically concerned with an improvement in a lubricating system for a sewing machine of the well-known Merrow type in which the stitch forming mechanism is driven, either directly or indirectly, by cams formed on a pair of cam cylinders mounted for rotation about parallel substantially horizontally disposed axes. A lubricating system for a machine of this type is shown in Patent No. 2,879,733. While the lubricating system disclosed in this patent has been generally satisfactory, it is found that under certain conditions the cam tracks formed around the outer surface of the cylindrical cams, and the cam followers disposed therein, have been unevenly lubricated, even when ample or an excess of lubricating :fluid is directed thereto.

Accordingly, it is an object of this invention to insure a more positive lubrication of the cam surfaces on the cam cylinders of the sewing machine, as well as the cam followers engaging the cam surfaces.

A further object of the invention is to provide a means for more positively lubricating the cam surfaces of the cam cylinders of the sewing machine, and the cam followers engaging the cam surfaces, without requiring an excess of lubricating fluid to be supplied thereto.

In the attainment of the foregoing, and other objects, an important feature of the invention resides in positioning an elongated cylindrical rod, having a low-pitched spiral groove extending around its outer surface throughout the length thereof, within the lubrication duct extending from the bearing surface on the end of the cam cylinder to the cam tracks on the outer surface of the cylinders. The diameter of the elongated rod is only slightly less than the diameter of the duct so that the spiral groove, or threads, formed on the outer surface of the rod form an obstruction to the flow of the lubricating fluid through the duct, thereby greatly reducing the rate at which the lubricating fluid passes through the duct. By reducing the rate of ow, the lubricating uid will be discharged into the cam track at a substantially constant rate throughout the rotation of the cam, thereby assuring that a quantity of lubricating uid will be discharged directly onto the cam follower upon each revolution of the cam cylinders.

Other objects and features of the invention will become apparent from the following detailed description taken with the accompanying drawings in which:

FIG. 1 is a front elevation view of a sewing machine embodying the present invention, with certain parts omitted to more clearly show the cam cylinders and stitch forming mechanism;

FIG. 2 is a partial longitudinal vertical section in a plane extending through the longitudinal axis of the cam cylinders, with certain parts broken away and others omitted;

FIG. 3 is an end elevation view of the cam cylinders taken on line 3 3 of FIG. 2;

FIG. 4 is an enlarged fragmentary sectional view of one of the cam cylinders shown in FIG. 2; and

FIG. 5 is an enlarged fragmentary sectional view ltaken on line 5 5 of FIG. 4.

Referring now to the drawings in detail, a high speed sewing ,machine of the well-known Merrow type is ilice lustrated generally by the numeral 10 and includes an external drive pulley 12 for rotatably driving a main shaft 14. Mounted on shaft 14 for rotation therewith is a rst cam cylinder 16 having a continuous row of radially extending gear teeth 18 formed around its outer periphery adjacent one end thereof. Gear teeth 18 en-gage a similar row of gear teeth 20` formed around the outer circurn ference of a sec-ond cam cylinder 22 mounted on shaft 24 for rotation therewith about an axis parallel to and vertically spaced from the axis of rotation of main shaft 14.

Cam cylinder 16 is provided with a .first endless cam track 28 extending around its outer surface, and a second endless cam track 30 extending around its outer surface and spaced axially from track 28. Cylinder 22 has a single continuous cam track 32 formed in its outer surface. As Ibest seen in FIG. 1, a first looper carrier 34, having a cam follower 36, is :pivotally mounted t-o the -machine as at 38, with cam follower 36 disposed within calm track 30 so that, upon rotation of cylinder 16, the lower looper 40 will be caused to reciprocate about pivotal mounting 38.

An upper looper carrier 42 is pivotally mounted, as at 44, to a sliding carriage, not shown. Carrier 42 includes a first cam follower 46 disposed within cam track 28 and a second cam follower 48 disposed within cam track 32 so that upon rotation of the cylinders 16 and 22 about their respective axes, cam followers 46 and 48 will impart a sliding movement to the looper carrier along an axis parallel to the axis of the cylinders, and due to the difference in the configuration of cam tracks 28 and 32 will simultaneously cause pivotal movement of the carrier 42 about the pivotal mounting 44 to import a compound movement to looper 50.

A needle 52 is reciprocally driven to cooperate with loopers 40 and 50 by an eccentric drive 54 on the end of shaft 24.

As is apparent from FIG. 1, the reaction force from the looper carriers acting on the cam surfaces of the cam cylinders will impart an oscillating axially directed force on the cylinders 16 and 22, with the direction and magnitude of the force passing through a complete cycle upon each revolution of the cylinders. In actual practice, the machine tolerances are such as to intentionally permit very limited axial movement of the cam cylinders, this axial movement being limited by thrust bearing surfaces 56 on each end of the respective cylinders 16 and 22 engaging corresponding thrust bearing surfaces on the machine frame.

Lubrication fluid is conventionally supplied to the thrust bearing surfaces on the ends of the cylinders 16 and 22 from the machines lubricating system. This lubricating fluid is supplied to the bearing surface on cylinder 16 through fluid duct 60 and to the bearing surface on cylinder 22 through duct 60 and groove 62 on shaft 24. To lubricate the cam surfaces of tracks 28, 30 and 32, and to lubricate the cam followers 46, 36 and 48 disposed within these cam tracks respectively, a lubrication conduit is formed within the respective cylinders and includes a rst cylindrical duct 64 having an open inlet 66 in thrust bearing surface 56 and extends to a point beneath the respective cam tracks. A second duct 68 extends from the bottom surface of the cam track radially inward to intersect duct 64 to form a continuous conduit from bearing surface 56 to the respective cam tracks. Since the means for lubricating the respective cam tracks and followers are similar, only one will be described in detail.

An elongated cylindrical rod 70, having a continuous spiral groove or thread 71 formed around its outer surface, as best seen in FIG. 4, is disposed within duct 64 of the lubrication conduit. Rod 70 is of suicient length to extend from a point adjacent inlet 66 throughout the length of duct 64, and extends beneath duct 68. Also, rod 70 has a diameter 72 only slightly less than the diameter 74 of duct 64, as illustrated in FIG. 5.

In operation of the machine, lubrication uid supplied to the bearing surface S6 and the corresponding bearing surface on the machine frame; forms a continuous film of fluid over the bearing surfaces 1as cam cylinders 16 and 22 are rotated about their respective longitudinal axes. As the cylinders are rotated, a portion of the fluid forming the film is picked up by the open inlet 66 and, since duct 64 of the conduit is slightly divergent from bearing surface S6 with respect to the longitudinal axis of the cylinder, this fluid which has been picked up will be driven by centrifugal force to How through duct 64 of the lubrication conduit and be discharged through duct 68 into the respective cam tracks. However, since cylinders 16 and 22 move slightly along the longitudinal axis, lubricating fluid is picked up by inlet 66 during only a portion of each revolution. Also, since only a film of fluid is dispersed over the bearing surface, fluid is picked up in inlet 66 at a relatively slow rate with the apparent result that oil is collected near inlet 65 until a suicient quantity is accumulated for the surface tension between the oil and the inner surface of duct 64 to be overcome by the centrifugal force, with this quantity then being propelled by centrifugal force through the duct 64 to be discharged into the cam track.

This somewhat intermittent iiow of the lubricating uid through the duct has, in the past, resulted in the lubricating fluid being discharged during any one or even several consecutive revolutions at a point remote from the cam followers withl the result that the lubricating Huid is thrown by centrifugal force from the cam track and the cam surfaces and cam followers do not receive proper lubrication.

By positioning the threaded rod 70 which fits loosely within the duct but which is of sucient size to occupy a major portion of the area of the duct, it has been found that the lubricating uid flows through and is discharged by the duct at a substantially continuous rate so that a portion of the fluid iiowing through the passage will be discharged upon the cam follower disposed within the cam track upon each revolution of the cam cylinder and thereby lubricate the cam tracks and cam followers. The centrifugal force caused by rotation of the cylindrical cams tends to force the rod toward the radially outer portion of the passage 64, but relative movement between the rod and passage 64 appears to be sufficient to break up any surface tension to provide for continuous ow through the duct.

While I have described a preferred embodiment of my invention, I wish it understood that I do not intend to be restricted solely thereto, but that I do intend to cover all embodiments thereof which would be apparent to one skilled in the art and which come Within the spirit and scope of my invention.

I claim:

1. In a sewing machine having a cam cylinder mounted for rotation about a longitudinal axis, a looper carrier having a cam follower disposed within an endless cam track formed on the outer surface of said .cylinder for driving said carrier, and means supplying lubricating fluid to a thrust bearing surface on lone end f said cylinder,

lubricant conveying means for said cam track and follower comprising a lfirst duct in said cylinder extending from an inlet port in said bearing surface divergently relative to the axis of said cylinder to a point located radially inwardly from said cam track, said inlet port being radially spaced from the axis of rotation of said cylinder, a second duct connected to the first duct at said point and extending outwardly to a port within said cam track, and an elongated metering rod loosely fitted within said rst duct and extending substantially throughout the length thereof.

2. In a sewing machine having a pair of cam cylinders mounted for rotation about spaced parallel axes, a looper carrier having cam followers disposed within endless cam tracks formed on the outer surface of said cylinders for driving the looper carrier and means supplying lubricating fluid to a thrust bearing surface on one end of said cylinders, and lubricant conveying means for said cam tracks and followers comprising a first duct in said cylinders extending from an inlet port in said bearing surfaces divergently relative to the axes of said cylinders to a point located radially inwardly from said cam tracks, respectively, said inlet ports being radially spaced from the axes of rotation of said cylinders, a second duct connected to said first duct at said point and extending outwardly to a port within said cam tracks, and an elongated metering rod loosely fitted within said iirst duct and extending substantially throughout the length thereof.

3. The sewing machine as defined in claim 2 wherein said metering rod has a low pitch spiral groove extending around its outer surface throughout its length.

4. In a sewing machine having a pair of cam cylinders mounted for rotation about spaced parallel axes, carn followers disposed within endless cam tracks formed in the outer surface of said cylinders for movement thereby upon rotation of said cylinders and means supplying lubricating uid to a thrust bearing surface on onel end of said cylinders, and lubricant conveying means for said cam tracks and followers comprising, a first duct in said cylinders extending from an inlet lport in said bearing surfaces divergently relative to the axis of said cylinder to a point located radially inwardly from each of the cam tracks respectively, said inlet ports being radially spaced from the axes of rotation of said cylinders, a second duct connected to said rst duct at said point and extending outwardly to a port within said cam tracks, and an elongated rod disposed within said rst duct and having a length substantially equal thereto, said rod having a low pitch spiral groove extending around its outer surface throughout its length and having a maximum diameter only slightly less than the diameter of said duct to reduce the rate of flow of lubricating fluid therethrough.

References Cited by the Examiner UNITED STATES PATENTS 2,749,865 6/ 1956 Kessler et al. ll2-256 2,879,733 3/1959 Pierce i12-256 2,999,474 9/ 1961 Mendles 112-256 3,146,745 9/1964 Schenkengel 112-256 JORDAN FRANKLIN, Primary Examiner. G. KRIZMANICH, Assistant Examiner. 

2. IN A SEWING MACHINE HAVING A PAIR OF CAM CYLINDERS MOUNTED FOR ROTATION ABOUT SPACED PARALLEL AXES, A LOOPER CARRIER HAVING CAM FOLLOWERS DISPOSED WITHIN ENDLESS CAM TRACKS FORMED ON THE OUTER SURFACE OF SAID CYLINDERS FOR DRIVING THE LOOP CARRIER AND MEANS SUPPLYING LUBRICATING FLUID TO A THRUST BEARING SURFACE ON ONE END OF SAID CYLINDERS, AND LUBRICANT CONVEYING MEANS FOR SAID CAM TRACKS AND FOLLOWERS COMPRISING A FIRST DUCT IN SAID CYLINDERS EXTENDING FROM AN INLET PORT IN SAID BEARING SURFACES DIVERGENTLY RELATIVE TO THE AXES OF SAID CYLINDERS TO A POINT LOCATED RADIALLY INWARDLY FROM SAID CAM TRACKS, RESPECTIVELY, SAID INLET PORTS BEING RADIALLY SPACED FROM THE AXES OF ROTATION OF SAID CYLINDERS, A SECOND DUCT CONNECTED TO SAID FIRST DUCT AT SAID POINT AND EXTENDING OUTWARDLY TO A PORT WITHIN SAID CAM TRACKS, AND AN ELONGATED METERING ROD LOOSELY FITTED WITHIN SAID FIRST DUCT AND EXTENDING SUBSTANTIALLY THROUGHOUT THE LENGTH THEREOF. 